This page provides instructions on how to upload images to the ARRSEpedia. Currently images cannot be uploaded directly so they will need to be hosted offsite. Once this is done then they can be linked from the page you want to display it on.
As already mentioned you will need to find an image hosted elsewhere. One place to consider is via the ARRSE Gallery although you should be aware that there will be a delay before this goes lives. There are loads of other places on the internet that also provide free image hosting and a few are listed below.
Once you have an image available for linking you will need to ascertain its URL. The best way to do this is to right click on it and select 'properties'. Most browsers allow you to select the URL using the mouse and copy it.
You should then paste the URL in the page in which you would like it to be displayed: